how many rounds to shoot out a barrel?

[cohunt]

I know this question is loaded, and depends on cartridge--but I was just curious if anyone could estimate

I have a type 99 arisaka in 7.7"JAP" got from a relative a while ago (handed down supposed war take home trophy)--this rifle still has the mum and matching numbers and is in extremely good condition, lacks the bolt dust cover but has a phenolic type of muzzle cover/cap on it--- the cleaning rod numbers do not match though --it has the AAC side bars on the sight too

Just for kicks, I bought some ammo for it to give it a whirl and he thing shot like crud--- so I stuck the bore scope down the barrel and was surprised at what I saw

starting at the chamber end, I saw little to no pitting with a very shiny smooth bore, the chamber was clean as well and the rifling was there but looked shallow---- as I proceed down the bore towards the muzzle the bore condition looked just as good but the rifling looked more worn--- by the time I got to the muzzle there was literally no rifling left-- ZERO-- it is truly a smooth-bore at the muzzle .

Any idea how many rounds of 7.7x58 it would take to shoot out a bore like this? it amazed me that the rifle exterior is so good, but it has clearly seen its days of shooting--- reload data shows it pushes a 180 gr bullet at about 2200fps-- that would be a fairly low pressure round I would think somewhere around 35-40000psi --probably take quite a while to shoot out that barrel --- these were supposedly chrome lined and polygonal rifling too

 

[rsmithsr]

the direction of WEAR is backwards.
most likely rust

 

[Hunterjones]

Perhaps all of it's cleaning was done unsupported from the bore and always...

 

[Hunterjones]

The bore END always....sorry. Should check my spelling more religiously....

 

[cohunt]

the direction of WEAR is backwards.
most likely rust

That's what I thought too on the wear but there is no pitting

I know they had lots of different kinds of ammo including ap, tracer, bimetal etc...could the different kinds of ammo (like tracer) ammo speeding up as it traveled down the barrel increase wear near the muzzle rather than the hot gas/throat burn out that we normally see? I wouldn't be surprised if it was cleaned from muzzle rather than breach either.

I have a 2nd one from same source but its horribly rusted- so bad that you have to kick the bolt handle with your boot to get it open--- when I get a chance I'll scope that bore to see if the wear is similar

 

[can1010]

it might have been like that from the beginning. the Japanese wwll rifles were not the best made. my grandfather had one if those rifles and you couldn't hit a barn with it.

 

[Hunterjones]

it might have been like that from the beginning. the Japanese wwll rifles were not the best made. my grandfather had one if those rifles and you couldn't hit a barn with it.

That sounds very plausible considering the bore is bright and shiny closer to the chamber.
One has to take an incredible amount of strokes with a cleaning rod to remove several thousandths of material........

 

[cohunt]

The older ones were actually very good rifles-- lots of care taken when made
But the "last ditch" ones were extreemly rough
This is an earlier model not anywhere near last ditch

 

[can1010]

try slugging the barrel it might have been tight from the beginning and that is just from wear because if I remember correct they a harder alloy for jackets because of the lack of copper. I remember my grandfathers ammo had what looked like steel jackets from the war

 

[oldfortyfiveauto]

The actions were noted for being exceptionally strong.

 

[Hunterjones]

My father's '06 Springfield all original 1930 rifle has a bore that you can't push a cotton patch thru without leaving an eighth of it in there. YEAH, she's rough AND pitted and rifling is really weak. Copper WILL NOT clean out of it. I have shot some sub inch groups with it at 100 yards shooting factory 165 grain ammo. MAKES ABSOLUTELY NO SENSE AT ALL...

 

[Deleted member 103481]

We have one that's minute of deer. Kicks like a mule. I'd imagine it was poor/non existent quality control during wartime on the rifles that did that, not round count.

that chambering should be "good" as in serviceable for well over5k I'd imagine since it's almost a 303 British ballistic duplicate and I think they were a 6-10k roundish estimate?

 

[cohunt]

The actions were noted for being exceptionally strong.

Iirc, they were the 2nd strongest actions made

 

[Greyfox]

The steel cleaning rod used from the muzzle end may very likely be the cause of the wear you describe, as opposed to round count. This type of wear is very common with the old lever actions which were cleaned from the muzzle end.